<?php
trait Log{
	public function save(){
		return __METHOD__;
	}
}
trait Comment{
	public function save(){
		return __METHOD__;
	}
}

class Topic{
	use Log,Comment{
		Log::save insteadof Comment;
		Comment::save as send;
	}

}

$topic=new Topic();
echo $topic->save();
echo $topic->send();
//输出 Log::save Comment::save
